There you can provide your kunaki.com username and password. That sets you up for using the integration in general.

Then to integrate a specific offer, go to the Edit Pricing & Delivery page of the offer.
At the bottom, you'd find the Physical Fulfillment Settings.
Check the box to Activate Physical Product Fulfillment.
Under "Please choose your product fulfillment service provider", select Kunaki.com.
Then provide your Kunkai Product ID(s) below in the Product ID fields. This assumes you already have product IDs in Kunaki.com

The Nanacast/Kunaki.com integration will then automatically calculate shipping fees based on the address information the customer provides on checkout.

If you enable physical fulfillment in the wizard when first creating the offer, the system will automatically add all the custom fields you need for shipping on the Notifications/Custom Fields page.
If you enable physical fulfillment later, after the offer is already created, you will need to add in all the custom fields related to shipping, on the Notifications/Custom Fields page.